How to know if you damaged your eyes during the eclipse

If you, like our nation's president, looked directly into Monday's eclipse, you might wonder: Did I just damage my eyes?
Whether by accident or disregard, untold masses looked at the sun with unshielded eyes during the must-see-safely event. By Monday afternoon, people were already freaking out about their eyes online.
The sun isn't more damaging to your eyes during a solar eclipse than on any other day. But as Ohio optometrist Michael Schecter told USA TODAY, the moon's covering makes it a...

Whether by accident or disregard, untold masses looked at the sun with unshielded eyes during the must-see-safely event. By Monday afternoon, people were already freaking out about their eyes online.

The sun isn't more damaging to your eyes during a solar eclipse than on any other day. But as Ohio optometrist Michael Schecter told USA TODAY, the moon's covering makes it a lot less painful to look at it for a lot longer. That makes it tempting for folks to peer over their cardboard eclipse glasses to see "what's really going on," Schecter said.

So how long can you look before getting hurt? Not long, says Jacob Chung, Chief of Opthalmology at New Jersey's Englewood Hospital.

"If you look at it for a second or two, nothing will happen," he said. "Five seconds, I'm not sure, but 10 seconds is probably too long, and 20 seconds is definitely too long."

PHOTOS: Total solar eclipse 2017

01/22

TOPSHOT - The "diamond ring effect" is seen during a total solar eclipse as seen from the Lowell Observatory Solar Eclipse Experience on August 21, 2017 in Madras, Oregon.
Millions will be able to witness the total eclipse that will touch land in Oregon on the west coast and continue through South Carolina on the east coast. / AFP PHOTO / STAN HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)

02/22

A view of the partial solar eclipse as seen from Beckman Lawn at Caltech in Pasadena, California on August 21, 2017.
Emotional sky-gazers on the US West Coast cheered and applauded Monday as the Sun briefly vanished behind the Moon -- a rare total solar eclipse that will stretch across North America for the first time in nearly a century. / AFP PHOTO / FREDERIC J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)

03/22

A total solar eclipse seen from the Lowell Observatory Solar Eclipse Experience on August 21, 2017 in Madras, Oregon.
Emotional sky-gazers on the US West Coast cheered and applauded Monday as the Sun briefly vanished behind the Moon -- a rare total solar eclipse that will stretch across North America for the first time in nearly a century. / AFP PHOTO / STAN HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)

04/22

A thin crescent sun is viewed just before totality during a solar eclipse seen from the Lowell Observatory Solar Eclipse Experience on August 21, 2017 in Madras, Oregon.
Emotional sky-gazers on the US West Coast cheered and applauded Monday as the Sun briefly vanished behind the Moon -- a rare total solar eclipse that will stretch across North America for the first time in nearly a century. / AFP PHOTO / STAN HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)

05/22

The sun's corona only is visible during a total solar eclipse between the Solar Temples at Big Summit Prairie ranch in Oregon's Ochoco National Forest near the city of Mitchell August 21, 2017.
The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century. / AFP PHOTO / Robyn Beck (Photo credit should read ROBYN BECK/AFP/Getty Images)

06/22

In this NASA handout, acomposite image, made from seven frames, shows the International Space Station as it transits the Sun at roughly five miles per second during a partial solar eclipse, Monday, Aug. 21, 2017 near Banner, Wyoming.

07/22

MADRAS, OR - AUGUST 21: In this NASA handout, The Bailey's Beads effect is seen as the moon makes its final move over the sun during the total solar eclipse on August 21, 2017 above Madras, Oregon. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. (Photo by Aubrey Gemignani/NASA via Getty Images)

08/22

JACKSON, WY - AUGUST 21: The sun is is in full eclipse over Grand Teton National Park on August 21, 2017 outside Jackson, Wyoming. Thousands of people have flocked to the Jackson and Teton National Park area for the 2017 solar eclipse which will be one of the areas that will experience a 100% eclipse on Monday August 21, 2017. (Photo by George Frey/Getty Images)

09/22

The sun's corona is visible as the moon passes in front of the sun during a total solar eclipse at Big Summit Prairie ranch in Oregon's Ochoco National Forest near the city of Mitchell on August 21, 2017.
The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century. / AFP PHOTO / Robyn Beck (Photo credit should read ROBYN BECK/AFP/Getty Images)

10/22

The total solar eclipse is viewd from Charleston, South Carolina, on August 21, 2017.
The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century. / AFP PHOTO / MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)

11/22

12/22

A total solar eclipse is seen from the Lowell Observatory Solar Eclipse Experience August 21, 2017 in Madras, Oregon.
Millions will be able to witness the total eclipse that will touch land in Oregon on the west coast and continue through South Carolina on the east coast. / AFP PHOTO / STAN HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)

13/22

BANNER, WY - AUGUST 21: In this NASA handout, the International Space Station (bottom right), with a crew of six onboard, is seen in silhouette as it transits the Sun at roughly five miles per second during a partial solar eclipse, August 21, 2017 near Banner, Wyoming. Onboard as part of Expedition 52 are: NASA astronauts Peggy Whitson, Jack Fischer, and Randy Bresnik; Russian cosmonauts Fyodor Yurchikhin and Sergey Ryazanskiy; and ESA (European Space Agency) astronaut Paolo Nespoli. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. (Photo by Joel Kowsky/NASA via Getty Images)

14/22

People watch the total solar eclipse in Charleston, South Carolina, on August 21, 2017.
The Sun started to vanish behind the Moon as the partial phase of the so-called Great American Eclipse began Monday, with millions of eager sky-gazers soon to witness "totality" across the nation for the first time in nearly a century. / AFP PHOTO / MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)

15/22

JACKSON, WY - AUGUST 21: The sun is partially eclipsed in the first phase of a total eclipse in Grand Teton National Park on August 21, 2017 outside Jackson, Wyoming. Thousands of people have flocked to the Jackson and Teton National Park area for the 2017 solar eclipse which will be one of the areas that will experience a 100% eclipse on Monday August 21, 2017. (Photo by George Frey/Getty Images)

16/22

Solar eclipse reaches totality as seen from Silverton, Oregon on Aug. 21, 2017.

17/22

Terrebonne, Oregon. Credit: Frank Mungeam

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Terrebonne, Oregon. Credit: Frank Mungeam

19/22

The solar eclipse nears totality around 1:15 p.m. Eastern time in Silverton, Oregon.

Any blurry vision won't kick in for a day or two, after the affected area swells "like an egg yolk" Schecter said. It can take months, even a year, for eyes to return to normal, he said — if it they do at all.

“You would basically get a burn on your central vision," Schecter said.

A 2001 study looked at 45 British patients who viewed the 1999 solar eclipse. While 20 patients claimed symptoms of affected vision, just five showed damage on their retinas. All five looked at the eclipse for 18 seconds or longer, Slate's Will Oremus noted.

One way to test at home whether you've damaged your eyes is to print off an Amsler Grid, Schecter said, a tool used to detect vision problems. Closing each eye separately, focus on the center dot and see whether the surrounding grid appears wavy, splotchy or distorted, he said.